U.S. patent application number 12/237281 was filed with the patent office on 2009-11-12 for 3-dimensional curved substrate lamination.
Invention is credited to Troy Edwards, Casey Feinstein, Steve Porter Hotelling, Andrew David Lauder, Kuo Sung, John Zhong.
Application Number | 20090277578 12/237281 |
Document ID | / |
Family ID | 40940606 |
Filed Date | 2009-11-12 |
United States Patent
Application |
20090277578 |
Kind Code |
A1 |
Sung; Kuo ; et al. |
November 12, 2009 |
3-Dimensional Curved Substrate Lamination
Abstract
A method of laminating a surface of a flexible material to a
surface of a rigid, curved material. The method includes pressing
an area of the surface of the flexible material into the surface of
the rigid, curved material with a holder to create a contact area
while the flexible material is conformed to the holder, which has a
curvature greater than a curvature of the rigid, curved material
surface; and changing the contact area between the surface of the
flexible material and the surface of the rigid, curved material
while maintaining pressure on the contact area until the surface of
the flexible material and the surface of the rigid curved material
are laminated.
Inventors: |
Sung; Kuo; (San Jose,
CA) ; Edwards; Troy; (San Jose, CA) ;
Feinstein; Casey; (San Jose, CA) ; Zhong; John;
(Cupertino, CA) ; Hotelling; Steve Porter; (San
Jose, CA) ; Lauder; Andrew David; (San Francisco,
CA) |
Correspondence
Address: |
APPLE C/O MORRISON AND FOERSTER ,LLP;LOS ANGELES
555 WEST FIFTH STREET SUITE 3500
LOS ANGELES
CA
90013-1024
US
|
Family ID: |
40940606 |
Appl. No.: |
12/237281 |
Filed: |
September 24, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61126864 |
May 7, 2008 |
|
|
|
61078325 |
Jul 3, 2008 |
|
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Current U.S.
Class: |
156/285 ;
156/325; 156/580; 156/60 |
Current CPC
Class: |
B32B 2037/264 20130101;
B32B 37/12 20130101; B32B 38/1866 20130101; B32B 37/10 20130101;
B32B 37/0053 20130101; B32B 2038/047 20130101; G06F 3/03543
20130101; Y10T 156/17 20150115; Y10T 156/1793 20150115; B29C
63/0073 20130101; B32B 38/1858 20130101; Y10T 156/1028 20150115;
B32B 2457/00 20130101; Y10T 156/10 20150115; B32B 17/064 20130101;
Y10T 156/18 20150115; B29C 63/0047 20130101; B32B 17/10 20130101;
B32B 37/003 20130101 |
Class at
Publication: |
156/285 ; 156/60;
156/325; 156/580 |
International
Class: |
B29C 65/00 20060101
B29C065/00 |
Claims
1. A method of laminating a surface of a flexible material to a
surface of a rigid, curved material, the method comprising:
pressing an area of the surface of the flexible material into the
surface of the rigid, curved material with a holder to create a
contact area while the flexible material is conformed to the
holder, which has a curvature greater than a curvature of the
rigid, curved material surface; and changing the contact area
between the surface of the flexible material and the surface of the
rigid, curved material while maintaining pressure on the contact
area until the surface of the flexible material and the surface of
the rigid curved material are laminated.
2. The method of claim 1, further comprising conforming the
flexible material to a curved surface of the holder.
3. The method of claim 1, wherein the rigid, curved material is
curved in a plurality of axes.
4. The method of claim 1, further comprising applying pressure
uniformly on the contact area.
5. The method of claim 1, further comprising initially establishing
the contact area at a center of the surface of the rigid, curved
material.
6. The method of claim 5, wherein changing the contact area
comprises: expanding the contact area towards an edge of the
surface of the rigid, curved material by increasing pressure
between the flexible area and the rigid, curved material in the
contact area.
7. The method of claim 1, further comprising initially establishing
the contact area at a first edge of the surface of the rigid,
curved material.
8. The method of claim 7, wherein changing the contact area
comprises: moving the contact area from the first edge to a second
edge of the surface of the rigid, curved material in response to
respective movement of the holder.
9. The method of claim 1, wherein changing the contact area
comprises: changing the shape of the contact area.
10. The method of claim 1, further comprising using an adhesive to
laminated the flexible material and the rigid curved material.
11. The method of claim 10, wherein the adhesive is selected from
the group consisting of pressure-sensitive adhesives (PSAs),
re-workable PSAs, thermoplastic film, thermoset film, thermal cure
liquid, UV curing liquid, and multiple-component adhesives.
12. The method of claim 10, further comprising heating at least one
of the flexible material and the rigid, curved material.
13. The method of claim 1, wherein the holder holds the flexible
material by suctioning vacuum holes.
14. The method of claim 1, further comprising pushing out air
bubbles formed between the flexible material and the rigid, curved
material as the contact area shifts.
15. The method of claim 1, further comprising conforming the rigid,
curved material in a base.
16. The method of claim 1, further comprising aligning the flexible
material with the holder on retractable alignment pins on the
holder.
17. The method of claim 1, wherein the holder is made of a
compliant material.
18. The method of claim 1, wherein changing the contact area
comprises changing an amount of force applied to the flexible
material and the rigid, curved material.
19. The method of claim 1, further comprising laminating a
stiffener to the flexible material.
20. The method of claim 1, wherein changing the contact area
comprising: moving the contact area from a first area of the
surface of the rigid, curved material to a second area of the
surface of the rigid, curved material in response to a rolling
motion of the holder.
21. The method of claim 1 further comprising walking a microbead
surface over the surface of the flexible material to remove air
bubbles between the laminated flexible material and the rigid,
curved material.
22. A method of laminating a surface of a flexible material to a
surface of a rigid, curved material comprising: forming a pressure
region between an area of the surface of the flexible material and
an area of the surface of the rigid, curved material, the pressure
region encompassing less than an entire area of the surface of the
flexible material; and changing at least one of a size of the
pressure region, a shape of the pressure region, and a position of
the pressure region to laminate together additional areas of the
surface of the flexible material and the surface of the rigid
curved substrate.
23. The method of claim 22, further comprising applying pressure
uniformly in the pressure region.
24. The method of claim 22, further comprising initially
establishing the pressure region at a center of the surface of the
rigid, curved material.
25. The method of claim 22, further comprising initially
establishing the pressure region at a first edge of the surface of
the rigid, curved material.
26. An apparatus for laminating a surface of a flexible material to
a surface of a rigid, curved material comprising: a first holder
that contacts the flexible material; a second holder that contacts
the rigid, curved material; and a pressure applying device adapted
to create and change a pressure region between the surface of the
flexible material and the surface of the rigid, curved material;
wherein the changing of the pressure region laminates the flexible
material to the rigid, curved material and removes air bubbles
between the laminated flexible material and the rigid, curved
material.
27. The apparatus of claim 26, wherein the rigid, curved material
is curved in a plurality of axes.
28. The apparatus of claim 26, wherein the pressure applying device
is adapted to apply uniform pressure on the rigid, curved
material.
29. The apparatus of claim 26, wherein the pressure region is
initially established at the center of the surface of the rigid,
curved material.
30. The apparatus of claim 29, wherein the pressure applying device
expands the pressure region from the center of the surface of the
rigid, curved material towards an edge of the rigid, curved
material by increasing pressure between the surface of the flexible
material and the surface of the rigid, curved material in the
pressure region.
31. The apparatus of claim 26, wherein the pressure region is
initially established at a first edge of the surface of the rigid,
curved material.
32. The apparatus of claim 31, wherein the pressure applying device
shifts the pressure region from the first edge of the surface of
the rigid, curved material to a second edge of the surface of the
rigid, curved material.
33. The apparatus of claim 26, wherein the pressure applying device
changes the shape of the pressure region.
34. The apparatus of claim 26, wherein the flexible material is a
substantially planar circuit board.
35. The apparatus of claim 26, wherein the flexible material is an
optically transparent material.
36. The apparatus of claim 35, wherein the optically transparent
material is a plastic with patterned indium tin oxide.
37. The apparatus of claim 26, wherein the flexible material
comprises a plurality of conductive traces on its surface and an
insulating layer deposited over the conductive traces.
38. The apparatus of claim 26, wherein the laminated flexible
material and the rigid, curved material are a part of a sensor
array.
39. The apparatus of claim 38, wherein the sensor array is a part
of a multi-touch mouse.
40. The apparatus of claim 26, wherein an adhesive is used to
laminated the flexible material and the rigid, curved material.
41. The apparatus of claim 40, wherein the adhesive is selected
from the group consisting of pressure-sensitive adhesives (PSAs),
re-workable PSAs, thermoplastic film, thermoset film, thermal cure
liquid, UV curing liquid, and multiple-component adhesives.
42. The apparatus of claim 26, wherein the first holder comprises
suctioning vacuum holes adapted to hold the flexible material.
43. The apparatus of claim 26, wherein the second holder comprises
suctioning vacuum holes adapted to hold the rigid, curved
material.
44. The apparatus of claim 26, wherein air bubbles between the
flexible material and the rigid, curved material are pushed out as
the pressure region changes.
45. The apparatus of claim 26, wherein the second holder comprises
retracted alignment pins for aligning the flexible material with
the second holder.
46. The apparatus of claim 26, wherein the first holder is made of
a deformable material.
47. The apparatus of claim 26, wherein the pressure applying device
is adapted to change an amount of pressure applied to the surface
of the flexible material and the surface of the rigid, curved
material.
48. The apparatus of claim 26, wherein the change of the pressure
region is in response to the shape of at least one of the first
holder and the second holder.
49. The apparatus of claim 26, further comprising a gimbal adapted
to control the movement of the pressure applying device.
50. The apparatus of claim 49, wherein the gimbal is adapted to
create a rolling motion of the first holder.
51. The apparatus of claim 26, further comprising a microbead
surface adapted to be walked over the flexible material to remove
air bubbles between the laminated flexible material and the rigid,
curved material.
52. The apparatus of claim 26, wherein the first holder is a
cylindrical roller adapted to roll across the surface of the rigid,
curved material during lamination.
53. The apparatus of claim 26, further comprising a plurality of
grippers adapted to hold a portion of the flexible material.
54. The apparatus of claim 53, wherein the grippers are adapted to
slide along the surface of the flexible material.
55. The apparatus of claim 52, wherein the second holder is a
cylindrical roller, and wherein the first holder and the second
holder rotate about an axis in opposite directions.
56. The apparatus of claim 26, wherein the first holder comprises a
flexible membrane adapted to achieve uniform pressure on the
surface of the rigid, curved material during lamination.
57. The apparatus of claim 56, wherein the flexible membrane is a
conformal material or a liquid or air filled sac.
58. The apparatus of claim 26, wherein the first holder comprises
an inflatable balloon.
59. The apparatus of claim 26, wherein at least one of the flexible
material and the rigid, curved material comprises perforations to
allow air bubbles to escape.
60. An apparatus for laminating a flexible material to a rigid,
curved material comprising: a first holder that contacts the
flexible material; a second holder that contacts the rigid, curved
substrate; and a moving device that moves at least one of the first
holder and the second holder, wherein the motion causes a pressure
region formed by contact between the flexible material and the
rigid, curved material to change in at least one of a size of the
pressure region, a shape of the pressure region, and a position of
the pressure region.
61. The apparatus of claim 60, wherein the laminated flexible
material and the rigid, curved material are a part of a sensor
array.
62. The apparatus of claim 61, wherein the sensor array is a part
of a multi-touch mouse.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent
Application Nos. 61/126,864 filed on May 7, 2008 and 61/078,325
file on Jul. 3, 2008, which are herein incorporated by
reference.
FIELD OF THE INVENTION
[0002] This invention relates to lamination of flexible or rigid
materials, and more particularly, to lamination of materials to a
curved, rigid substrate.
BACKGROUND OF THE INVENTION
[0003] Conventional lamination processes are adequate for
laminating a substantially flat/planar material to a substantially
flat/planar substrate. For example, in the field of electronic
devices, many conventional methods exist to laminate a planar
printed circuit board to a planar substrate, such as another planar
printed circuit board, to form a single, laminated circuit board.
However, conventional techniques may not work when the substrate is
substantially curved.
SUMMARY OF THE INVENTION
[0004] Laminating a flexible material to a curved substrate can
pose several difficulties, particularly when the process is applied
in the field of electronic devices. For example, it may be more
difficult to prevent air bubbles from getting trapped between a
flexible material and a curved substrate during lamination than
between rigid straight material. In some electronics applications,
for example, laminates must meet strict quality requirements that
limit the number and/or size of trapped air bubbles. If a laminate
has too many trapped air bubbles, or if the air bubbles are too
large, the laminate must often be discarded as defective, resulting
in lost time and money. Even if the adhesive used in the defective
laminate can be reworked to reduce trapped bubbles, the
re-lamination process would still result in lost time. In addition,
the materials used in the laminates of some electronic devices can
be relatively delicate. This limits the maximum pressure that can
be applied during lamination.
[0005] In one embodiment of the invention, a lamination system
includes a base and an upper portion. The base includes a lower
holder. The upper portion includes an upper holder and control
circuitry. The lower holder includes a lower contact surface that
is placed in contact with a non-lamination surface of a substrate,
such as the non-lamination surface of the substrate. The upper
holder includes an upper contact surface that is placed in contact
with a non-lamination surface of a flexible material, such as the
non-lamination surface of the flexible material. The lower holder
and the upper holder may each be mounted to a motion block. The
lower and upper motion blocks can provide various types of motion
to the holders ranging from single axis motion to fully articulated
motion, depending on the requirement of the particular lamination
system. Different embodiments of the disclosed lamination system
are described in more detail below.
[0006] During the lamination process, the lamination surfaces are
brought together with an adhesive material in between. Various
types of adhesives can be used, including pressure-sensitive
adhesives (PSAs), re-workable PSAs, thermoplastic film, thermoset
film, thermal cure liquid (single or multiple components),
ultraviolet (UV) cure liquid, and multiple-component adhesives that
cure at room temperature. The adhesive(s) may be applied to the
substrate, the flexible material, or both. In addition, the
adhesive(s) may be applied as a sheet or sheets, and/or one or more
regions of liquid adhesive. As the lamination surfaces are brought
into contact, a force-applying area of the upper contact surface
and a force-applying area of the lower contact surface apply
opposing forces to press together the substrate and the flexible
material in a pressure region between the upper and lower
force-applying areas. The portions of the substrate and the
flexible material in the pressure region are pressed together and
laminated with the adhesive material. Either or both of the lower
holder and the upper holder may be heated to improve adhesive
properties. Lamination may also be performed at or below room
temperature.
[0007] In another embodiment, a lower holder is a base chuck formed
of a rigid material, such as glass or a metal. The lower holder has
a lower contact surface that is shaped to conform to a
non-lamination surface of a curved substrate. An upper holder is a
vacuum chuck formed of a compliant material, such as rubber. The
upper holder has an upper contact surface with vacuum holes (not
shown) to hold a non-lamination surface of a flexible printed
circuit board (PCB) in place on the upper contact surface. Thus,
flexible PCB is forced into the shape of upper contact surface. In
one embodiment, the upper contact surface initially has a higher
curvature than the lower contact surface.
[0008] During an early stage of a lamination process, the upper
holder is moved along a z-axis direction towards the lower holder,
causing a lamination surface of flexible PCB to contact a
lamination surface of curved substrate initially at a single-point,
causing the lamination surfaces to be pressed together in a
pressure region between force-applying areas of the upper contact
surface and the lower contact surface, respectively. As the
lamination process continues, the upper holder is pressed further
in the z-direction, against the lower holder. The increasing
pressure causes the size of the pressure region to grow larger.
[0009] During a latter part of the lamination process, after upper
holder has been moved further along the z-axis towards lower
holder. Because upper holder is made of a compliant material, the
motion has caused the upper holder to deform. Now, the contact area
between the lamination surface of the PCB and the lamination
surface of the curved substrate becomes greater than it was during
the early stage of the lamination process. The larger contact area
causes the lamination surfaces to be pressed against each other in
a larger pressure region between larger force-applying areas of the
upper contact surface and the lower contact surface, respectively.
In this embodiment, the process continues until the pressure region
expands to cover the entire lamination surfaces.
[0010] Because the pressure region begins as a single point and
expands from that point during the lamination process, surrounding
air may be less likely to become trapped between the flexible PCB
and curved substrate as a result of air being pushed out and away
from the center as the process continues. Therefore, the lamination
system according to this embodiment may potentially reduce or
eliminate the formation of air bubbles caused during lamination. In
addition, because the upper holder is formed of a compliant
material, the present example embodiment may be better-suited for
lamination of relatively delicate materials.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1A illustrates examples of a curved substrate and a
flexible material according to embodiments of the invention.
[0012] FIG. 1B illustrates the curved substrate and the flexible
material of FIG. 1A laminated together according to embodiments of
the invention.
[0013] FIGS. 2A and 2B are cross-sectional views showing details of
the curvature of the substrate in the y-direction and the
x-direction, respectively, according to embodiments of the
invention.
[0014] FIG. 3 is a more detailed, cross-sectional view of a portion
of the flexible material according to embodiments of the
invention.
[0015] FIG. 4A illustrates an exemplary curved surface for a sensor
array according to embodiments of this invention.
[0016] FIG. 4B illustrates an exemplary "butterfly" pattern for a
sensor array according to embodiments of this invention.
[0017] FIG. 4C illustrates an exemplary two-strip sensor array
pattern according to embodiments of this invention.
[0018] FIG. 4D illustrates an exemplary three-strip sensor array
pattern according to embodiments of this invention.
[0019] FIG. 4E illustrates an exemplary flat sensor pattern in a
"snail" pattern that can be applied to a curved surface according
to embodiments of this invention.
[0020] FIG. 5 illustrates an exemplary lamination system according
to embodiments of the invention.
[0021] FIGS. 6-8 are cross-sectional views illustrating the
operation of a lower holder and an upper holder of an exemplary
lamination system according to embodiments of the invention.
[0022] FIGS. 9A and 9B are cross-sectional views illustrating the
operation of a lower holder and an upper holder of another
exemplary lamination system according to embodiments of the
invention.
[0023] FIGS. 10A-C are cross-sectional views illustrating the
operation of a lower holder and an upper holder of another
exemplary lamination system according to embodiments of the
invention.
[0024] FIGS. 11A and 11B illustrate the operation of a lower holder
and an upper holder of another exemplary lamination system
according to embodiments of the invention.
[0025] FIGS. 12A-E each shows three top views taken along the
z-axis of the substrate at progressively increasing times during
the second stage to illustrate various ways in which pressure
region can change depending on the different configurations of the
lamination system according to embodiments of the invention.
[0026] FIGS. 13A and 13B illustrate a substrate and flexible
material with multi-axis curvatures according to embodiments of the
invention.
[0027] FIGS. 14A-D illustrate the operation of a lower holder and
an upper holder of another exemplary lamination system according to
embodiments of the invention.
[0028] FIG. 15 illustrates the operation of an upper holder of
another exemplary lamination system according to embodiments of the
invention.
[0029] FIGS. 16-18 illustrate the operation of a lower holder and
an upper holder of another exemplary lamination system according to
embodiments of the invention.
[0030] FIGS. 19-21 illustrate the operation of a lower holder and
an upper holder of yet another exemplary lamination system
according to embodiments of the invention.
[0031] FIG. 22 illustrates the operation of a lower holder and an
upper holder of yet another exemplary lamination system according
to embodiments of the invention.
[0032] FIGS. 23A-B, 24A-C, and 25 illustrate various exemplary
alignment structures that can be used to help align a flexible
material according to embodiments of the invention.
[0033] FIG. 26 is a perspective view illustrating a 2-step process
for laminating a printed circuit board (PCB) to a curved substrate
according to embodiments of the invention.
[0034] FIG. 27 is a perspective view illustrating a 1-step process
for laminating a PCB to a curved substrate.
[0035] FIGS. 28A-C illustrates the operation of a lower holder and
an upper holder of another example lamination system according to
embodiments of the invention.
[0036] FIGS. 29A-B illustrate a post-lamination device and process
according to embodiments of the invention.
[0037] FIG. 30 illustrates a perforated substrate according to
embodiments of this invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0038] In the following description of preferred embodiments,
reference is made to the accompanying drawings, in which it is
shown by way of illustration specific embodiments in which the
invention can be practiced. It is to be understood that other
embodiments can be used and structural changes can be made without
departing from the scope of the embodiments of this invention.
[0039] For the sake of clarity, many of the figures do not show an
adhesive used in the lamination processes described below. However,
it is understood that an adhesive or other approach that allows the
fixing together of two materials may be used in these
processes.
[0040] The present disclosure relates to apparatus and methods for
laminating a rigid or flexible material to a curved substrate.
[0041] FIGS. 1A and 1B are perspective drawings illustrating
examples of a curved substrate 101 and a flexible material 103 that
may be laminated together according to embodiments of the
invention. In particular, FIG. 1A shows the substrate 101 and the
flexible material 103 before lamination. As illustrated, the
substrate 101 and the flexible material 103 have lamination
surfaces 105 and 107, respectively, adapted to be laminated
together. The substrate 101 and the flexible material 103 also have
non-lamination surfaces 109 and 111, respectively, that are
opposite the lamination surfaces. In this embodiment, the substrate
101 may be a glass plate that is curved along more than one axis,
i.e., multi-axis curvature. Other substrates suitable for
lamination may include plastics, ceramics, and other materials. As
illustrated in FIG. 1A, substrate 101 is curved in both the x-axis
and the y-axis. A closer view of the curvature of substrate 101 is
provided in FIGS. 2A and 2B.
[0042] FIG. 1B shows the substrate 101 and the flexible material
103 having their respective lamination surfaces (not shown) fixed
together as a result of the lamination process.
[0043] FIGS. 2A and 2B are cross-sectional views showing details of
the curvature of the substrate 101 in the y-direction and the
x-direction, respectively. The degree of curvature in each axis may
or may not be the same. In this embodiment, the figures show that
the curvature of the substrate 101 along the y-axis is generally
greater than the curvature along the x-axis. In addition, the
curvature of the substrate 101 can vary along an axis. For example,
FIG. 2A shows a portion 201 nearer to an edge of the substrate 101
along the y-axis and a portion 203 nearer to the center of the
substrate 101 along the y-axis. Portions 201 and 203 are magnified
to illustrate that the curvature of portion 201 is greater than the
curvature of portion 203. In other words, the substrate 101 is
straighter near its center than at its edges.
[0044] Referring again to FIG. 1A, in this embodiment, flexible
material 103 is a substantially planar circuit board. In
particular, the circuit board is formed by, for example, depositing
circuit elements, such as resistors, capacitors, transistors,
and/or conductive traces (e.g., wires) onto a flexible board
substrate. An insulating layer can be deposited over the circuit
elements to protect against environmental elements such as
moisture, as well as to provide a smoother surface for lamination.
However, the surface of the insulating material may not be
perfectly smooth. In other embodiments, the flexible material 103
may be an optically transparent material, such as a plastic with
patterned indium tin oxide (ITO).
[0045] FIG. 3 is a more detailed, cross-sectional view of a portion
of the flexible material 103. FIG. 3 shows conductive traces 301 on
a flexible board substrate 303, and an insulating layer 305
deposited over the conductive traces 301. Because the conductive
traces 301 protrude from the surface of the board substrate 303,
the surface of the insulating layer 305 has "peaks" 307 over the
conductive traces 301 and "valleys" 309 between the conductive
traces 301. Therefore, the surface insulating layer 305, which is
the lamination surface 307 in this embodiment, is not perfectly
smooth.
[0046] The flexible material 103 need not be a continuous sheet,
and may have cutouts, slits, or other characteristics that allow
the flexible material 103 to be conformed to a curved surface.
FIGS. 4A-4E illustrates various forms of the flexible materials
103, such as flexible circuit boards, and curved surfaces.
[0047] FIG. 4A illustrates an exemplary curved surface for a sensor
array according to embodiments of this invention. A typical flex
circuit sensor array applied to the inside of this surface may tend
to wrinkle, buckle, or snap.
[0048] FIG. 4B illustrates an exemplary "butterfly" pattern for a
sensor array according to another embodiment of the invention. This
pattern can be formed using a flat array and applied to a curved
surface without wrinkling.
[0049] FIG. 4C illustrates an exemplary two strip sensor array
pattern according to yet another embodiment of this invention.
[0050] FIG. 4D illustrates an exemplary three strip sensor array
pattern according to yet another embodiment of this invention. Both
patterns shown in FIGS. 4C and 4D can also be formed from a flat
array and applied to a curved surface.
[0051] FIG. 4E illustrates an exemplary flat sensor pattern in a
"snail" pattern that can be applied to a curved surface according
to yet another embodiment of this invention.
[0052] The above-described curved or three-dimensional shaped
sensor patterns in FIGS. 4A-4E may be placed under or over a curved
substrate, for example, a glass or plastic cover. These sensors
patterns can be used in a variety of multi-touch devices, for
example a multi-touch mouse.
[0053] In another embodiment, the sensor array can be formed on a
thermal plastic substrate material that can be reformed with heat.
In this configuration the sensor array may be draped across a mold
and then heated to form a curved sensor array shape. Alternatively,
the substrate may be vacuum formed inside a cavity. The traces in
the array, which may for example be made out of copper, may be made
flexible enough to withstand this type of reshaping.
[0054] Laminating a flexible material to a curved substrate can
pose several difficulties, particularly when the process is applied
in the field of electronic devices. For example, it may be more
difficult to prevent air bubbles from getting trapped between a
flexible material and a curved substrate during lamination than
between rigid straight material. In some electronics applications,
for example, laminates must meet strict quality requirements that
limit the number and/or size of trapped air bubbles. If a laminate
has too many trapped air bubbles, or if the air bubbles are too
large, the laminate must often be discarded as defective, resulting
in lost time and money. Even if the adhesive used in the defective
laminate can be reworked to reduce trapped bubbles, the
re-lamination process would still result in lost time.
[0055] In addition, the materials used in the laminates of some
electronic devices can be relatively delicate. This limits the
maximum pressure that can be applied during lamination. For
instance, the substrate 101 in FIG. 1A may be glass, which is
breakable under pressure. Similarly, the flexible material 103 in
FIG. 1A may be a circuit board that can only sustain a limited
amount of pressure to prevent damages to its circuit elements.
[0056] In view of the foregoing, FIG. 5 illustrates a lamination
system 500 according to an embodiment of the invention. Lamination
system 500 includes a base 503 and an upper portion 507. The base
503 includes a lower holder 505. The upper portion 507 includes an
upper holder 509 and control circuitry 511. The lower holder 505
includes a lower contact surface 513 that is placed in contact with
a non-lamination surface of a substrate, such as the non-lamination
surface 109 of the substrate 101 in FIG. 1A. The upper holder 509
includes an upper contact surface 515 that is placed in contact
with a non-lamination surface of a flexible material, such as the
non-lamination surface 111 of the flexible material 103 of FIG. 1A.
The lower holder 505 and the upper holder 509 may each be mounted
to a motion block 517, 519. The lower and upper motion blocks 517,
519 can provide various types of motion to the holders ranging from
single axis motion to fully articulated motion, depending on the
requirement of the particular lamination system. Different
embodiments of the disclosed lamination system are described in
more detail below.
[0057] During the lamination process, the lamination surfaces are
brought together with an adhesive material in between. Various
types of adhesives can be used, including pressure-sensitive
adhesives (PSAs), re-workable PSAs, thermoplastic film, thermoset
film, thermal cure liquid (single or multiple components),
ultraviolet (UV) cure liquid, and multiple-component adhesives that
cure at room temperature. The adhesive(s) may be applied to the
substrate, the flexible material, or both. In addition, the
adhesive(s) may be applied as a sheet or sheets, and/or one or more
regions of liquid adhesive. As the lamination surfaces are brought
into contact, a force-applying area of the upper contact surface
515 and a force-applying area of the lower contact surface 513
apply opposing forces to press together the substrate and the
flexible material in a pressure region between the upper and lower
force-applying areas. The portions of the substrate and the
flexible material in the pressure region are pressed together and
laminated with the adhesive material. Either or both of the lower
holder 505 and the upper holder 509 may be heated to improve
adhesive properties. Lamination may also be performed at or below
room temperature.
[0058] As described in more detail in the following exemplary
embodiments, the upper holder 509 and the lower holder 505 may be
formed such that the pressure region may change during the
lamination process. For example, in some embodiments, the pressure
region changes in position during the lamination process. In other
embodiments, the pressure region changes in size and/or shape
during the lamination process. In still other embodiments, the
pressure region changes in position and in size/shape during the
lamination process. In yet other embodiments, the shape and
position of the pressure region remain the same. By changing
position, size, shape, and/or other aspects of the pressure region,
problems such as the formation of trapped air bubbles may be
minimized.
[0059] FIGS. 6-8 are cross-sectional views illustrating the
operation of a lower holder and an upper holder of an embodiment of
the disclosed lamination system. Referring to FIG. 6, a lower
holder 601 is a base chuck formed of a rigid material, such as
glass or a metal. Lower holder 601 has a lower contact surface 603
that is shaped to conform to a non-lamination surface 605 of a
curved substrate 607. An upper holder 609 is a vacuum chuck formed
of a compliant material, such as rubber. The upper holder 609 has
an upper contact surface 611 with vacuum holes (not shown) to hold
a non-lamination surface 613 of a flexible printed circuit board
(PCB) 615 in place on the upper contact surface 611. Thus, flexible
PCB 615 is forced into the shape of upper contact surface 611. As
shown in FIG. 6, the upper contact surface 611 initially has a
higher curvature than the lower contact surface 603.
[0060] FIG. 7 shows lower holder 601 and upper holder 609 during an
early stage of a lamination process. Specifically, the upper holder
609 is moved along a z-axis direction towards the lower holder 601,
causing a lamination surface 701 of flexible PCB 615 to contact a
lamination surface 703 of curved substrate 607 initially at a
single-point, causing the lamination surfaces 701 and 703 to be
pressed together in a pressure region 705 between force-applying
areas 707 and 709 of the upper contact surface 611 and the lower
contact surface 603, respectively.
[0061] As the lamination process continues, the upper holder 609 is
pressed further in the z-direction, against the lower holder 601.
The increasing pressure causes the size of the pressure region 705
to grow larger.
[0062] FIG. 8 shows the lower holder 601 and the upper holder 609
during a latter part of the lamination process, after upper holder
609 has been moved further along the z-axis towards lower holder
601. Because upper holder 609 is made of a compliant material, the
motion has caused the upper holder 609 to deform. Now, the contact
area between the lamination surface 701 of the PCB 615 and the
lamination surface 703 of the curved substrate 607 becomes greater
than it was during the early stage of the lamination process shown
in FIG. 7. The larger contact area causes the lamination surfaces
701, 703 to be pressed against each other in a larger pressure
region 801 between larger force-applying areas 803 and 805 of the
upper contact surface 611 and the lower contact surface 603,
respectively. In this embodiment, the process continues until the
pressure region expands to cover the entire lamination surfaces
701, 703.
[0063] Because the pressure region begins as a single point and
expands from that point during the lamination process, surrounding
air may be less likely to become trapped between the flexible PCB
615 and curved substrate 607 as a result of air being pushed out
and away from the center as the process continues. Therefore, the
lamination system according to this embodiment may potentially
reduce or eliminate the formation of air bubbles caused during
lamination. In addition, because the upper holder 609 is formed of
a compliant material, the present example embodiment may be
better-suited for lamination of relatively delicate materials.
[0064] FIGS. 9A and 9B are cross-sectional views illustrating the
operation of a lower holder and an upper holder of another
exemplary lamination system according to embodiments of the
invention. The system of FIGS. 9A and 9B is similar to the system
of FIGS. 6-8. Referring to FIG. 9A, the system includes a base 901
including a lower holder 903 with a lower contact surface 905. The
system also includes an upper portion, press 907, having an upper
holder 909 with an upper contact surface 911. One difference
between this embodiment (illustrated in FIGS. 9A and 9B) and the
previous embodiment (illustrated in FIGS. 6-8) is that, in this
system, the upper holder 909 is a rigid chuck and the lower holder
903 is of deformable, compliant material, such as rubber. Also, the
system illustrated in FIGS. 9A and 9B includes retractable
alignment pins 913 protruding from the lower holder 903, and vacuum
holes 915 through both the upper and lower holders 909, 903.
[0065] In this system, a curved substrate 917 is fixed to upper
contact surface 911 by positioning the substrate over vacuum holes
915 and applying a vacuum to the holes. A flexible PCB 919 is fixed
to the lower holder 903 by using the vacuum holes 915 through the
lower holder 903. The retractable alignment pins 913 provide a
guide when positioning and fixing the flexible PCB 919 onto the
lower holder 903. The vacuum holes 915 keeps the flexible PCB 919
warped over the lower holder 903 before lamination.
[0066] FIG. 9B illustrates the system of FIG. 9A during a
lamination process. As in the embodiment described above, the upper
holder 909 is moved along a z-axis direction towards the lower
holder 903 so that the respective lamination surface of the curved
substrate 917 and the flexible PCB 919 are pressed together at a
pressure region that begins at a contact point 991 because the
curvature of the lower holder 903 is higher than the upper holder
909. The pressure region expands as the upper holder 909 continues
to be pressed against the lower holder 903 because the lower holder
903 is made of a compliant, deformable material and deforms as it
receives increasing pressure. As the pressure region expands, the
retractable alignment pins 913 may be retracted and the lamination
surface of the curved substrate 917 can eventually be in contact
with the entire area of the lamination surface of the PCB 919.
Alternately, lower holder 903 may be moved toward upper holder 909
in the z-axis direction to achieve the same lamination result.
[0067] FIGS. 10A-C are cross-sectional views illustrating the
operation of a lower holder and an upper holder of another
exemplary lamination system according to embodiments of this
invention. The system of FIGS. 10A-C is similar to the system
illustrated in FIGS. 9A and 9B. Referring to FIG. 10A, the system
includes a base 1002 including a lower holder 1004 with a lower
contact surface 1006. A bottom substrate 1016 is held by the lower
holder 1004 by a vacuum chuck (not shown) or mechanical features of
the lower holder 1004. The system also includes an upper portion,
for example, a press 1008. The upper portion includes an upper
holder 1010. In this embodiment, the upper holder 1010 has a
flexible membrane 1012 adapted to hold a top substrate 1014 in a
pre-form position. In various embodiments, the top substrate 1014
may be held by a vacuum chuck (not shown) or other mechanical
features of the upper holder 1010. The membrane 1012 may be a
conformal material (e.g., silicone rubber) or a liquid or air
filled sac.
[0068] FIGS. 10B and 10C illustrate the system of FIG. 10A during a
lamination process. Referring to FIG. 10B, similar to previously
disclosed embodiments, the upper holder 1010 is moved towards the
lower holder 1004 so that the bottom surface of the top substrate
1014 becomes in contact with and presses against the top surface of
the bottom substrate 1016. Because the curvature of the lower
holder 1004 is less than the curvature of the upper holder 1010,
the initial contact between the top substrate 1014 and the bottom
substrate 1016 is made at the center of the top surface of the
bottom substrate 1016, as a result of the movement of the upper
holder 1008 towards the lower holder 1004 in the z-direction.
[0069] FIG. 10C illustrates the next stage in the lamination
process. As the upper holder 1010 continues to exert pressure on
the lower holder 1004 after the initial contact between the top
substrate 1014 and the bottom substrate 1016, the flexible membrane
1012 of the top holder starts to deform. As a result, the initial
pressure point expands from the center of the top surface of the
bottom substrate 1016 towards the edges of the bottom substrate
1016 until the top substrate 1014 and the bottom substrate 1016 are
completely laminated to each other, as illustrated in FIG. 10C.
Because the upper holder 1010 includes a flexible membrane 1012 in
this embodiment, pressure is applied evenly in all directions
against the bottom substrate 1016 in the lamination process. The
upper holder 1010 may also be made of other types of material that
allows it to apply pressure evenly in all directions in the
lamination process. Either or both of the lower holder 1004 and the
upper holder 1010 may be heated to improve adhesive properties. In
various embodiments, the process illustrated in FIGS. 10A-C can be
applied in a reverse setup by rotating the illustrated system 180
degrees so that the lower holder is on top and the upper holder is
at the bottom.
[0070] FIGS. 11A and 11B illustrate the operation of a lower holder
and an upper holder of another exemplary lamination system
according to embodiments of the invention. In this system, a curved
substrate 1101 is placed on a lower holder 1103 that includes fixed
alignment pins 1105. A flexible material 1109 is secured over the
lower holder 1103 by placing the alignment holes 1107 on the
flexible material 1109 over the alignment pins 1105. FIG. 11A
illustrates a first stage of a lamination operation in which an
upper holder 1111 is moved along the z-axis towards the lower
holder 1103. The upper holder 1111 is mounted to the upper motion
block 519 of FIG. 5 by a motion articulator such as a gimbal 1113
(other articulators could include ball joints, hinges or other
mechanical linkage) to provide articulated motion including
translational and rotational motion along multiple axes. As the
upper holder 1111 approaches the lower holder 1103, a leading
portion 1115 of the upper holder 1111 contacts a first area 1117 of
flexible material 1109 and pushes the area 1117 towards the
substrate 1101. In various embodiments, the initial contact between
the leading portion 1115 and the first area 1117 of the flexible
material may be at different angles. The upper holder 1111
continues moving along the z-axis until the leading portion 1115
causes the first area 1117 of the flexible material 1109 to contact
a first area 1119 of the substrate 1101, creating a pressure region
(not shown).
[0071] FIG. 11B illustrates a second stage of the lamination
operation. The second stage begins after the first area 1117 of
flexible material 1109 contacts the first area 1119 of the
substrate 1101. In the second stage, the upper holder 1111 rotates
about the y-axis until the top flat surface 1110 of the upper
holder 1111 is parallel to the bottom flat surface 1120 of the
lower holder as the upper holder 1111 moves towards the lower
holder 1103 along the z-axis. This second stage motion causes the
pressure region 1121 to change in size, shape, and/or position. How
the pressure region 1121 changes may depend on several factors,
such as the shapes and rigidity of the upper and lower holders
1111, 1103, the type and amount of force/motion applied through the
gimbal 1113 during operation, and other factors.
[0072] FIGS. 12A-E each shows three top views taken along the
z-axis at progressively increasing times during the second stage to
illustrate the various ways in which the pressure region 1121
evolves depending on the different configurations that will now be
described. In the figures, the shaded areas represent pressure
region 1121. The views are taken at times t=0 (beginning of second
stage, initial contact of first area 1117 and first area 1119), t=1
(approximately midway through second stage), and t=2 (approximately
the end of the second stage).
[0073] Referring to FIG. 12A, if both holders are formed of rigid
materials and have constant, single-axis curvature (i.e.,
cylindrical curvature as shown in FIGS. 11A and 11B), the curvature
of upper holder 1111 is greater than the curvature of lower holder
1103, and an even force is applied through the gimbal such that
upper holder 1111 rolls across lower holder 1103 and applies a
constant pressure during the second stage, then the size and shape
of pressure region 1121 will remain substantially constant, but the
position of pressure region 1121 will move along the lamination
surfaces as shown in FIG. 12A.
[0074] Referring to FIG. 12B, if the configuration is the same as
in FIG. 12A, except that the curvature of upper holder 1111 is the
same as the curvature of lower holder 1103, the size of pressure
region 1121 will increase, but the type of shape will remain
roughly rectangular. As illustrated, in this embodiment, the aspect
ratio of the rectangular shape will change. The position of one
side 1210 of the rectangle will remain substantially fixed while
the position of the opposite side 1212 will move farther away as
shown in FIG. 12B.
[0075] Referring to FIG. 12C, the configuration of the lamination
system is the same as in FIG. 12A, except that one or both of the
holders is formed of a compliant material and the force along the
z-axis towards the lower holder 1103 is constantly increased
through gimbal 1113 during the first half of the second stage and
then constantly decreased during the last half of the second stage.
As the result, the size of pressure region 1121 will increase in
the first half of the second stage and decrease in the last half of
the second stage, the shape of the pressure region 1121 remains
rectangular though the aspect ratio will change, and the position
will move along the lamination surfaces as shown in FIG. 12C.
[0076] Referring to FIG. 12D, the configuration of the lamination
system used here is the same as in FIG. 12A, except that both
holders have constant, multi-axis curvature (e.g., curvature along
the x-axis and the y-axis as shown in FIGS. 13A and 13B), and the
upper holder 1111 has greater curvature than the lower holder 1101
in both axes. As the result, the size and shape of the pressure
region 1121 remains fairly constant throughout the second stage and
the position of the pressure region 1121 may change as shown in
FIG. 12D.
[0077] As is apparent in FIG. 12D, the entire area of the
lamination surfaces may not be exposed to the pressure region 1121
in the single pass of upper holder 1111. This is different from the
configurations of FIGS. 12A-12C which covers the entire lamination
surfaces in a single pass. Therefore, it may be desirable to drive
the upper holder 1111 through additional motion to cover the entire
lamination surface. For example, the gimbal 1113 could provide an
additional rotation motion around the x-axis to roll the upper
holder 1111 to one side, and then provide a motion substantially
reverse of the previous motion, resulting in the pressure region
changes shown in FIG. 12E.
[0078] In all the configurations described above, the substrate
curvature is not limited to single axis (cylindrical curvature).
Arbitrary multi-axis curvature may be supported by any of these
configurations. FIG. 13A shows a variation of the lamination system
of FIG. 11A. As illustrated, both the upper holder 1302 and the
lower holder 1308 have contact surfaces 1310, 1312 that have
multi-axis curvature. In various embodiments, the curvature of the
upper contact surface 1310 may or may not be the same as the
curvature of the lower contact surface 1312. As illustrated in FIG.
13B, the curved substrate 1306 is fixed to the lower holder 1308
and substantially adapts the curvature of the lower contact surface
1312 of the lower holder 1308. Similarly, the flexible material
1304 may conform to the curvature of the upper contact surface 1310
of the upper holder 1302.
[0079] FIGS. 14A-D illustrate the operation of a lower holder and
an upper holder in a side-to-side lamination process according to
another embodiment of the invention. This embodiment shares some of
the features of the embodiments illustrated in FIGS. 10A-C and
FIGS. 11A-B. Referring to FIG. 14A, the system includes a base 1402
including a lower holder 1404 with a lower contact surface 1406. A
bottom substrate 1416 is held by the lower holder 1404 by a vacuum
chuck (not shown) or mechanical features of the lower holder 1404.
The system also includes an upper portion, for example, a press
1408. The upper portion has affixed to it an upper holder 1410. In
this embodiment, the upper holder 1410 has a flexible membrane 1412
adapted to hold a top substrate 1414 in a pre-form position. In
various embodiments, the top substrate 1414 may be held by a vacuum
chuck (not shown) or other mechanical features of the upper holder
1410. The membrane 1412 may be a conformal material (e.g., silicone
rubber) or a liquid or air filled sac. As illustrated in FIG. 14A,
prior to the start of the lamination process, the press/upper
holder 1408, 1410 and the base/lower holder 1402, 1406 are
positioned like an open book, where the press/upper holder 1408,
1410 is the "book cover" and the base/lower holder 1402, 1406 is
the rest of the book. The press 1408 and the base 1402 may or may
not be in contact with each other. Both the top substrate 1414 and
the bottom substrate 1416 are held on top of their respective
holders 1410, 1404. The left edge of the press 1408 is
approximately aligned with the right edge of the base 1402 so that
when the upper holder 1410 rotates counter clockwise about the
y-axis, the upper substrate 1414 can be in position to make contact
with the bottom substrate 1416 and become laminated to the bottom
substrate 1416.
[0080] Referring to FIG. 14B, as the upper portion rotates about
the y-axis, a first portion 1420 of the upper substrate 1414
initially comes into contact with a first portion 1422 of the
bottom substrate 1416. A pressure region (not shown) is formed at
the initial point of contact between the first portion 1420 of the
upper substrate 1414 and the first portion 1422 of the bottom
substrate 1416. After the initial contact, the upper portion
continues to rotate about the y-axis, causing the pressure region
to change in size, shape, and/or position. How the pressure region
changes can depend on several factors, such as the shapes and
rigidity of the upper and lower holders, the type and amount of
force/motion applied to by the press during operation, and other
factors. In various embodiments, the pressure region may change,
for example, as illustrated in FIGS. 12A-12E.
[0081] FIG. 14C illustrates a stage in which the side-to-side
lamination process is at approximately its halfway point where the
press 1408 and the base 1402 are substantially parallel to each
other and the upper holder 1410 is in contact and applying pressure
to the center region of the lower holder 1404. Because the adhesion
force between the first portion 1420 of the upper substrate 1414
and the first portion 1422 of the bottom substrate 1416 is higher
than the holding force between the upper holder 1410 and the upper
substrate 1414, the first area 1420 of the upper substrate 1414 in
FIG. 14B is now detached from the upper holder 1410 and laminated
to the first area 1422 of the bottom substrate.
[0082] FIG. 14D illustrates the final stage of the side-to-side
lamination process. As illustrated, the upper portion continues to
rotate about the y-axis from where it was in FIG. 14C. The center
portion of the upper substrate 1414 is now detached from the upper
holder and laminated to the center portion of the lower substrate
1416. The pressure region has shifted beyond the center of the
lower holder 1404 and reached the other side of the lower holder
1410. This allows the upper substrate 1414 to be completely
laminated to the bottom substrate 1422. In this embodiment,
pressure is applied evenly in all directions by the nature of the
material that forms the membrane.
[0083] The system of FIGS. 14A-D may be overturned and the above
described side-to-side lamination process may be repeated in the
opposite direction to make sure that the substrates are completed
laminated and rid of any air bubbles that remains between the
substrates.
[0084] FIG. 15 illustrates the operation of an upper holder of
another exemplary lamination system according to embodiments of the
invention. In this system, an upper holder 1501 is substantially
cylindrical and is formed of a compliant material such as rubber.
For the sake of clarity, a lower holder is not illustrated. FIG. 15
also shows a flexible material 1503 held at one end by grippers
1505. The flexible material 1503 may include detachable tabs (not
shown) to be held by the grippers in some embodiments. During a
lamination operation, upper holder 1501 rolls across a
non-lamination surface 1509 of the flexible material 1503 to press
the flexible material 1503 and a multi-axis curved substrate 1509
together. As upper holder 1501 rolls across flexible material 1503,
the upper holder 1501 deforms to conform to the shape of the
substrate 1509. During the lamination process, the grippers 1505
may, for example, hold a fixed portion of the flexible material
1503, such as an edge portion or the detachable tabs. In another
embodiment, the grippers 1505 may slide along the surface of
flexible material 1503 while providing enough resistance to reduce
slack in the unattached portion of the flexible material 1503.
[0085] FIGS. 16-18 illustrate the operation of a lower holder and
an upper holder of another exemplary lamination system according to
embodiments of the invention. Referring to FIG. 16, this system
includes an upper holder 1601 and a lower holder 1603 that are
substantially cylindrical wheels that can rotate about an axis.
Note that diameter of one or both wheels may be chosen based on the
curvature of the substrate 1605. Each holder is formed of a
compliant material, such as rubber, foam, a flexible air- or
fluid-filled bag, etc. A curved substrate 1605 and a flexible
material 1607 are fed in as the holders 1601, 1603 rotate in
opposite directions to grab the substrate 1605 and the flexible
material 1607 and pull them into a working space 1609 between the
upper holder 1601 and the lower holder 1603. In the working space
1609, the upper holder 1601 and the lower holder 1603 exert
opposing forces on the flexible material 1607 and the curved
substrate 1605, respectively, which causes the formation of a
pressure region 1611 where lamination occurs. The portion of the
flexible material 1607 in the working space is forced to be
conformed to the upper holder 1601 and, as a result of the forces,
any air bubbles between the flexible material 1607 and the curved
substrate 1605 are pushed out.
[0086] FIG. 17 illustrates a more detailed view of the working
space 1609. In particular, FIG. 17 shows the opposing
force-applying areas 1701 and 1703 of flexible material 1701 and
substrate 1703, respectively. As seen in FIG. 17, it may be
possible to make the pressure region 1611 a small size, which may
allow for a greater pressure to be applied in the pressure region
1611 while reducing the chance of breakage of the lamination
material. This may be particularly useful in the case that the
lamination materials are delicate, for example, if curved substrate
1605 is made of glass. FIG. 18 is a front view illustrating that
rolling surfaces 1801 and 1803 of the upper holder 1601 and the
lower holder 1603 are deformable and can conform to the shape of
the laminate materials along the y-axis.
[0087] FIGS. 19-21 illustrate the operation of a lower holder and
an upper holder of another exemplary lamination system according to
embodiments of the invention. Referring to FIG. 19, this system
includes an upper holder 1901 that is formed of a hollow,
expandable bag or balloon, and a lower holder 1903 that is a rigid
base. A curved substrate 1905 is placed on lower holder 1903 with a
non-lamination surface of the substrate in contact with the lower
holder 1903. A flexible material 1907 is placed on the curved
substrate 1905 with a non-lamination surface exposed to upper
holder 1901. A pump (not shown) is coupled to the upper holder 1901
to pump, for example, air into and out of the upper holder 1901, so
that the upper holder 1901 can be made to expand and contract.
[0088] FIG. 20 shows the beginning of a lamination process of the
system of FIG. 19. The upper holder 1901, which is not inflated, is
moved along z-axis towards lower holder 1903 until the surface of
upper holder 1901 pitch contact with the non-lamination surface of
flexible material 1907. Once contact is made, the upper holder 1901
stops moving in the z-axis. The pump (not shown) coupled to the
upper holder is turned on to inflate the upper holder 1901 by
pumping air into the upper holder 1901. As shown in FIG. 21, the
shape of the upper holder 1901 changes as it inflates, such that a
pressure region is first formed at the point of first contact and
then expands outward in a substantially radial direction towards
the perimeter of the flexible material 1907. This can cause air to
be forced from the center to the perimeter of the laminate, helping
to eliminate air bubbles in and/or surrounding the pressure
region.
[0089] FIG. 22 illustrates the operation of a lower holder and an
upper holder of another example lamination system according to
embodiments of the invention. The system shown in FIG. 22 is
similar to the system shown in FIGS. 19-21. However, upper holder
1901 is inflated with gas or liquid before it is moved into contact
with flexible material 1907. Once upper holder 1901 is inflated, it
is lowered into contact with flexible material 1907. The motion
continues downward after contact, deforming upper holder 1901 and
creating a pressure region that increases in size from the initial
contact point radially outward towards the perimeter. Note, while
the upper holder 1901 is moving downward in contact with the
flexible material 1907, air or gas may or may not be pumped into or
out of the upper holder 1901. In other words, the degree of
inflation of the upper holder 1901 may be increased or decreased
while it is moving in contact with the flexible material 1907.
[0090] FIGS. 23A-B, 24A-C, and 25 illustrate various example
alignment structures that can be used to help align a flexible
material 2301 when placing the flexible material 2301 onto a curved
substrate 2303. FIGS. 23A-B are perspective views showing the
flexible material 2301 formed with break off tabs 2305 for
alignment. In this embodiment, break off tabs 2305 extend from the
periphery of the flexible material 2301 and have holes that can be
fit over alignment pins (not shown) to help with alignment. In
another embodiment, the holes of break off tabs 2305 can be used to
visually align the flexible material 2301 by matching the holes
with fiducials, markers, such as dots or X's (not shown).
[0091] FIGS. 24A-C show the alignment holes 2401 in the flexible
material 2301 that allow for visual alignment of the flexible
material 2301 using fiducials on the substrate 2303. FIGS. 24A and
24B show two different full views of the flexible material, and
FIG. 24C shows a magnified view of a hole 2401 aligned with a
fiducial 2402 on the substrate 2303.
[0092] FIG. 25 shows another layout of alignment holes. As
illustrated, the alignment holes 2501 in the flexible material 2301
are an opposite ends of the flexible material 2301.
[0093] FIG. 26 is a perspective view illustrating a 2-step process
for laminating a PCB 2605 to a curved substrate 2607, and then
laminating a stiffener to the PCB back. First, alignment holes 2601
are placed over alignment pins 2603 to align the PCB 2605 with a
glass, curved substrate 2607. The substrate 2607 is held in
position against a base 2609 using vacuum holes (not shown). In a
first step of a lamination process, an upper holder 2611 is moved
along the z-axis in the direction towards the base 2609. After
making contact with the PCB 2605, the upper holder 2611 continues
moving towards the base 2609. This movement causes the PCB 2605 to
break away from the break away tabs 2613 and become laminated onto
the substrate 2607.
[0094] In a second step of the lamination process, a stiffener (not
shown) is placed onto the exposed PCB 2605 surface, and pressed
downward by the upper holder 2611 to be laminated to the PCB/glass
laminate. The stiffener may be a rigid material with a curvature
that matches the curvature of the substrate 2607,
[0095] FIG. 27 is a perspective view illustrating a 1-step process
for laminating a PCB 2705 to a glass curved substrate 2707, while
at the same time laminating a stiffener 2709 to the PCB back. As in
the embodiment shown in FIG. 26, the alignment holes 2701 are
placed over alignment pins 2703 to align the PCB 2705 with the
glass curved substrate 2707. The substrate 2707 is held in position
against a base 2711 using vacuum holes (not shown). In this system,
the stiffener 2709 is held to the upper holder 2713 by, for
example, vacuum holes (not shown). In one example embodiment, the
stiffener 2709 may be fit into a negative cutout of the upper
holder 2713. Therefore, as the upper holder 2713 moves downward
towards the base 2711, and the upper holder presses the PCB 2705
together with substrate 2707, the upper holder 2713 is also
pressing the stiffener 2709 together with the PCB 2705. Therefore,
only a single step (i.e., a single press and release motion) is
needed to form a 3-layer laminate of the substrate 2707, the PCB
2705, and the stiffener 2713.
[0096] FIGS. 28A-C illustrates the operation of a lower holder and
an upper holder of another exemplary lamination system according to
embodiments of the invention. In particular, FIG. 28 is one example
of many possible combination methods that utilize different
features, configurations and processes in the previously described
embodiments. The system of FIG. 28, for example, combines some
aspects of the system of FIGS. 6-8 (e.g., rigid lower holder, upper
holder with vacuum holes, lowering upper holder along z-axis to
make contact at the center of the lower holder first) with some
aspects of the system of FIGS. 11, 12, and 13A (e.g., rigid upper
holder, rolling motion of upper holder in y-axis).
[0097] Referring to FIG. 28A, an upper holder 2801 having vacuum
holes (not shown) that hold a flexible material 2803 is lowered
along a z-axis to contact a rigid curved substrate 2805 at a center
contact point. A pressure region 2807 is formed at the center
contact point initially and then moved along the surface of the
laminates by applying a rolling motion of the upper holder 2801.
Next, as illustrated in FIG. 28B, as the rolling motion is applied
in one direction, one end 2809 of the flexible material 2803 in the
opposite direction begins to buckle and/or separate from the upper
holder 2801. Finally, as illustrated in FIG. 28C, the upper holder
2801 rolls in the opposite direction, moving the pressure region
2807 over the buckled portion 2809 of the flexible material 2803 to
complete the lamination.
[0098] By combining different aspects of embodiments, the pressure
region causing lamination can be changed in many different ways to
achieve the same lamination result.
[0099] FIGS. 29A-B illustrate a post-lamination device and process
according to embodiments of the invention. Referring to FIG. 29A,
an example microbead surface 2900 is shown. The microbead surface
2900 includes a body 2901 in which a plurality of springs 2903 are
positioned. Springs 2903 are coupled to microbeads 2905 such that
an outward (direction by arrows in FIG. 29A) force is applied to
each microbead. The outward forces of springs 2903 are countered by
a plurality of collars (not shown) that hold the microbeads 2900
within the body 2901 while allowing a portion of the microbeads
2905 to protrude from the body 2901. Thus, the protruding portion
of each microbead 2905 can apply a force that is proportional to
the spring constant of its corresponding spring 2903.
[0100] FIG. 29B illustrates a post-lamination process in which the
microbead surface 2950 is walked slowly over the surface of a
laminate 2907. The motion can be automatic or manual. In this
example, the surface of the laminate 2907 has peaks 2909 and
valleys 2911 as a result of, for example, underlying conductive
traces (not shown). As the microbead surface 2900 is moved across
the surface, the microbeads can potentially protrude down into a
valley 2911 and push an air bubble 2913 to a perimeter of the
laminate 2907, thereby preventing air bubbles from being trapped in
the laminate 2907. In particular, the microbead surface 2900 can be
formed such that, for example, the sizes of the microbeads 2905,
the distances between the microbeads 2905, and/or the pattern
created by the microbead protrusion conform to an underlying
conductive trace pattern, potentially increasing the efficiency of
the post-lamination process. In one embodiment, the microbeads 2905
are 1 mm to 5 mm in size and are 4 mm to 10 mm apart.
[0101] FIG. 30 illustrates a substrate 3201 including perforations
3203. Perforations in either or both of the substrate 3201 and the
flexible material 3203 can help air bubbles escape.
[0102] As one skilled in the art would readily understand after
reading the disclosure herein, various aspects of the configuration
of the lamination system can be adjusted to produce many different
changes in the pressure region during a lamination process. The
aspects of the configuration include, but are not limited to, the
size and shape of the upper and lower holders, the materials used
in the holders, the adhesives used, the materials to be laminated
together, the different rotational motions, such as rolls, pitches
and yaws, and various translational motions along different axes,
the use of multiple passes, and post-lamination processes.
Furthermore, any of the foregoing processes that utilize a rigid
lower holder and a rigid upper holder can be used to laminate a
rigid material to a rigid curved substrate. In other words, in
those example embodiments, and others that one skilled in the art
would readily recognize, the material that is laminated to a rigid
curved substrate need not be flexible, but may be rigid.
[0103] In addition, any of the foregoing processes may be applied
in a vacuum chamber or in ambient pressure. A compliant or
spring-supported layer may be added to any of the holders not
explicitly listed as compliant, particularly as a method of
uniformly distributing applied forces across the substrates. Also,
adjustment for alignment in axes other than the z-axis (lateral
dimensions x and y, as well as yaw, pitch and roll) may be added to
one or both the lower and the upper holders, particularly to
facilitate alignment. Lamination by any of the foregoing methods
may be followed by an autoclave process, in which individual parts
may or may not be placed in vacuum bags, to increase bond quality
and reduce trapped bubbles. In addition, alignment pins as shown in
the figures do not represent all possible locations or
configurations of alignment features. Fiducials and optically
assisted alignment are also supported in the forgoing
processes.
[0104] Although embodiments of this invention have been fully
described with reference to the accompanying drawings, it is to be
noted that various changes and modifications will become apparent
to those skilled in the art. Such changes and modifications are to
be understood as being included within the scope of embodiments of
this invention as defined by the appended claims.
* * * * *